//IEEE 1588 PTP Protocol slave implementation
static void sync_clock(int times, int *sock, struct sockaddr_in *master) {
char useless_buffer[FIXED_BUFFER];
int i; //to prevent C99 error in for loop
printf("Running IEEE1588 PTP...");
fflush(stdout);
send_packet(sock, "ready", 5, NULL, master);
//run protocol num of times determined by master
for(i = 0; i < times; i++) {
sync_packet(sock, master);
delay_packet(sock, master);
receive_packet(sock, useless_buffer, sizeof(useless_buffer), NULL, NULL);
}
printf("Done!\n");
}
int main(int argc, char**argv)
{
int sockfd,n;
struct sockaddr_in servaddr;
if (argc < 5)
{
printf("usage: udpcli <IP address>, udp <port number>, srcPort, dstPort\n");
exit(1);
}
if (sscanf (argv[2], "%i", &ConnectionPort)!=1) { printf ("error - not an integer"); exit(-1); }
if (sscanf (argv[3], "%i", &srcPort)!=1) { printf ("error - not an integer"); exit(-1); }
if (sscanf (argv[4], "%i", &dstPort)!=1) { printf ("error - not an integer"); exit(-1); }
sockfd=socket(AF_INET,SOCK_DGRAM,0);
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr=inet_addr(argv[1]);
servaddr.sin_port=htons(ConnectionPort);
// Here we use file descriptor to avoid I/O block at receive side.
int timeout =3000;
struct timeval tv;
fd_set readfds, active_fs;
tv.tv_sec = 0;
tv.tv_usec = 3000;
FD_ZERO(&readfds);
FD_SET(sockfd, &readfds);
double elapsedTime;
int flag =0;
//blocking way, it measures the latency in a better way!
char sendline[1400];
char recvline[1400];
memset(sendline, 0,1400);
sync_packet(sockfd, sendline, &servaddr);
n=recvfrom(sockfd,recvline,1400,0,NULL,NULL);
//fputs(recvline,stdout);
int ack = *(int *) recvline;
int seq = *(int *) (recvline +4);
int port = *(int *) (recvline+20);
printf("Is is sync ack? %d and %d and the port number is %d\n", ack, seq, port);
if (ack==2 && seq == SEQUENCENUM && n ==28)
{
goto confirmed;
}
confirmed:
{
int HeaderLength = sizeof(header);
char AckMesg[HeaderLength];
header * ackHeader = (header *)AckMesg;
ackHeader->action = 3;
ackHeader->sequenceNum = SEQUENCENUM;
gettimeofday(&t2, NULL);
elapsedTime =(t2.tv_usec - t1.tv_usec) + (t2.tv_sec - t1.tv_sec)*1000000;
printf("Time is %f\n",elapsedTime);
sendto(sockfd,AckMesg,sizeof(header),0,(struct sockaddr *) &servaddr,sizeof(struct sockaddr_in ));
/*
Here we add keep alive messages to show the mobility can be handled for packets on the fly
*/
while(1){
sleep(5);
keepalive(sockfd, (struct sockaddr *)&servaddr);
}
return 0;
}
}
